Two-dimensional frequency comb from cascaded nonlinear mixing of a multi-color soliton in an integrated microresonator

Abstract

We present the creation of a two-dimensional frequency comb in a single integrated microring resonator through its dual pumping. We demonstrate experimentally and theoretically that dual-pumping allows for the creation of a multi-color soliton with a single group rotation velocity yet multiple phase rotation velocities, yielding multiple soliton eigenfrequencies (i.e. colors). We show that, thanks to the material's nonlinearity, its eigenfrequencies can cascade through four-wave mixing, creating a comb. Because this dimension is orthogonal to the azimuthal mode number dimension, the extracted frequency comb is ultimately a two-dimensional one.